The range of function y = LG [1 / (x ^ 2-1)] is

The range of function y = LG [1 / (x ^ 2-1)] is

The true number is greater than 0
1/(x^2-1)>0
So x ^ 2-1 > 0
There is no maximum value for x ^ 2-1
So the denominator range is all positive numbers
So the 1 / (x ^ 2-1) range is all positive numbers
So the range of Y is r

The range of the function y = 1-lg (2 + x ^ 2) is
Such as the title

∵2+x²≥2
∴lg(2+x²)≥lg2
∴y∈(-∞,1-lg2)
(Sogou is still very useful: & sup2;, ∩, ∩, ∞, ∈...)

The range of function y = 1-lg (e ^ x + e ^ - x) is

Because e ^ X and e ^ - X are all greater than 0, then the basic inequality is e ^ x + e ^ - x > = 2, so LG (e ^ x + e ^ - x) > = LG2. If and only if x = 0, the equation holds. Therefore, the original formula is less than or equal to 1-lg2

Find the value of 3 / 2Y + X / 4 * 5 + X / 5 * 6 + X / 6 * 7 +... + X / 2009 * 2010

Original formula = 3 / 2Y + (1 / 4-1 / 2010) x = 3 / 2Y + 1003x / 4020

20 out of 21 - (for minus) 2 out of 7 + 1 out of 2 = 4 out of 15-5 out of 9 + 1 out of 6 = 5 out of 9 + 3 out of 4-1 out of 2 = 9 out of 1-2=
1 / 2 + 1 / 6 + 1 / 20 = 23 / 24 - 5 / 14 - 1 / 6=
Same denominator addition and subtraction (> ﹏﹏)

20 of 21 - (for minus) 2 of 7 + 1 of 2 = 7 of 6
4 / 15-5 / 9 + 1 / 6 = - 11 / 90
5 / 9 + 3 / 4-1 / 2 = 29 / 36
9 of 1-2-1 of 9 = - 65 of 18
1 / 2 + 1 / 6 + 1 / 20 = 43 / 60
23-14 / 24, 5-6 / 24 = 73 / 168

Finding the integer solution of X + y + xy = 0
X ^ 2 + (a + b) + AB = (x + a) (x + b), x = 1, then 1 + (a + b) + AB = (1 + a) (1 + b)

If x + y + xy = 0 and 1 is added to both sides of the equation, we can get the following formula:
x+y+xy+1=1
The factorization is as follows
(x+1)(y+1)=1
So there are:
(x+1)=(y+1)=1
Or: (x + 1) = (y + 1) = - 1
The solution is: x = y = 0
Or: x = y = - 2

On the eve of tree planting day, a unit carries out tree planting activities. It takes 80 hours for one person to plant trees. Now, some people plant trees for 5 hours first. Due to the emergency of the unit
How many people should be arranged to plant trees first if two more people are required to complete the task within 4 hours and their work efficiency is the same?

X people should be arranged to plant trees first
X*5*1/80+(X+2)*4*1/80=1
X/16+(X+2)*1/20=1
X/16+X/20+1/10=1
9X/80=9/10
X=8
Eight people should be arranged to plant trees first

Let a and B be non-zero real numbers, then the possible values of | a | a + | B | B make up the elements of the set______ ．

When a ＞ 0, B ＞ 0, when a ＞ 0, B |a-a + |b | B = AA + BB = 2; when a ＞ 0, B ＜ 0, B |a + |a + |a + |b | B = AA-BB = 0; when a ＜ 0, B ＜ 0, when a ＜ 0, B |a + | B | B | B | B |a + |a + |a + |a-a-a-a + |a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-b |a | B | B | B thepossible values of B are - 2, 0, 2. So the answer is - 2, 0, 2

In order to prepare for the party, students of class 7 (8) went to a convenience store to buy 70 bottles of a certain beverage twice, sharing 188 yuan. The price of the beverage is as follows: the number of bottles (bottles) is not more than 3030, the unit price is not more than 5050, and the unit price is 32.52. How many bottles of the beverage should be purchased twice?

Let x bottle be purchased for the first time, then (70-x) bottle be purchased for the second time; (1) when x < 20, 3x + 2 (70-x) = 188, the solution is: x = 48 > 20; (2) when 20 < x < 30, 3x + 2.5 (70-x) = 188, the solution is: x = 26; (3) when 30 < x < 40, 2.5x + 2.5 (70-x

Simplify (ab-b Square) △ A-B of ab

(ab-b Square) △ A-B of ab
=b(a-b)×ab/(a-b)
=ab²